Final answer:
Senator Joseph McCarthy's tactics and unsupported accusations during the 1950s created an atmosphere of fear and paranoia in the US, leading many Americans to be afraid to challenge him.
Step-by-step explanation:
The fear during the 1950s can be considered well-founded due to the actions and tactics of Senator Joseph McCarthy. McCarthy used unfair tactics and made unsupported accusations of Communist infiltration in the US government, a period known as McCarthyism. McCarthy's techniques created an atmosphere of fear and paranoia, leading to many Americans being afraid to challenge his attacks.
McCarthy's unsupported accusations were influential because very few Americans were willing to challenge him, including President Eisenhower. McCarthy's tactics and the fear they created were indirectly challenged by journalist Edward Murrow and playwright Arthur Miller, who exposed the parallels between Cold War hysteria and historical examples like the Salem Witch Trials.